That not an argument to support China using stolen tech, though. Just because US did a bad thing, doesn't make it ok for China to do so.

The argument is that they should expect to be hacked when using tech stolen from other countries. By pointing out US also steal technologies, you're only arguing that the US should also expect to be hacked, an idea no one was arguing against. You're basically arguing against a point that hasn't been brought up, yet.